17-Heteroaroyl esters of corticosteroids. 2. 11 beta-Hydroxy series.

The preparation and topical antiinflammatory potencies of a series of 17-furoyl and -thenoyl esters of 9 alpha-fluoro-11 beta-hydroxy-16 methyl and 9 alpha-chloro-11 beta-hydroxy-16-methyl corticosteroids are described. The 17 alpha-esters were introduced to the 9 alpha-fluoro 11-ketones or to the appropriate delta 9(11) compounds by direct acylation with the appropriate heteroaryl carbonyl chloride in the presence of 4-(dimethylamino)pyridine. Functionalization of the C ring was completed by standard methods. The most extensively studied heterocyclic acyl group was 2-furoyl, but 3-furoyl and 2- and 3-thenoyl derivatives were also investigated. Antiinflammatory potencies were measured in mice by a 5-day modification of the Tonelli croton oil ear assay. The most potent topical antiinflammatory agents were 1e, dexamethasone 17-(2'-furoate) 21-propionate, and 2c, the 21-chloro 17-(2'-furoate) in the 9 alpha-chloro series, both being 6 times as potent as betamethasone 17-valerate. Several other 9 alpha-chloro-11 beta-hydroxy-17-heteroaryl carboxylates (2a, 2b, 2d, and 2g) were at least 4 times as potent as betamethasone 17-valerate. Evaluation of 2c in the clinic confirmed that the compound is a potent topical antiinflammatory agent in humans.

Synthesis and structure-activity studies of corticosteroid 17-heterocyclic aromatic esters. 1. 9 alpha, 11 beta-dichloro series.

The preparation and topical antiinflammatory potencies of a series of 9 alpha, 11 beta-dichloro-16-methyl corticosteroid 17-heteroaryl carboxylates are described. The 17-acyl group was introduced to the 9 alpha, 11 beta-dichloro 21-acetate by direct acylation with the appropriate heteroaryl carbonyl chloride in the presence of 4-(dimethylamino)pyridine. Alternatively, the 21-functionalized 17-hydroxy delta 9(11) compound was acylated at 17, followed by C-ring chlorination. The most extensively studied heterocyclic acyl functionality was the 2-furoyl, but the 3-furoyl, and 2- and 3-thenoyl derivatives were also investigated. Antiinflammatory potencies were measured in mice by a 5-day modification of the Tonelli croton oil ear assay. The most potent topical antiinflammatory compounds were 17-heteroaryl esters in the 16 alpha-methyl series where the 21-substituent was chloro or fluoro. Thus 2p [21-chloro 17-(2'-furoate)] was 8 times as potent as betamethasone valerate, while 2s [21-fluoro 17-(2'-furoate)], 2r [21-chloro 17-(2'-theonate)], and 2v [6 alpha-fluoro 21-chloro 17-(2'-furoate)] were 3 times as potent as betamethasone valerate.

A novel class of potent topical antiinflammatory agents: 17-benzoylated, 7 alpha-halogeno substituted corticosteroids.

As part of continued efforts in the synthesis of structurally novel corticosteroids, a number of 17 alpha-benzoylated, 7 alpha-halogeno substituted prednisolones were tested for topical antiinflammatory activity. 7 alpha-Chloro, 7 alpha-bromo, and 7 alpha-iodo corticosteroids were synthesized by hydrogen halide addition to 1,4,6-triene-3-ones. The 7 alpha-fluoro substituted steroid was obtained by reaction of the appropriate 7 beta-hydroxy compound with N,N-diethyl(2-chloro-1,1,2-trifluoroethyl)amine. Antiinflammatory potencies were obtained using a croton oil-induced inflammation in the ears of mice. In this assay the greatest effect of a 7 alpha-halogen was observed in the 16 alpha-methylprednisolone series, where 7 alpha-fluoro and 7 alpha-bromo substitution yielded corticosteroids with topical potencies significantly higher than those of the corresponding 17,21-dipropionate analogs. Surprisingly, little potency enhancement due to 7 alpha-halogenation was discerned in the 16 beta-methylprednisolone series.